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A promising direction in solving the problem of energy saving at agribusiness facilities is the use of an integrated approach - the principle of trigeneration, in which thermal energy is generated based on the thermoelectric method, which involves the use of special modules from thermoelements based on the Peltier effect. On the basis of this method, a climate control system for agro-industrial complex objects has been developed, represented by a block diagram and an equivalent functional model. To assess its compliance with a certain quality of the control process during the transition of the system to a new operating mode, a comparative analysis of the use of linear and nonlinear control algorithms for thermoelectric modules was carried out. In this case, the nonlinearities were set by two saturation links corresponding to the Saturation blocks in the MatLAB Simulink environment. With the help of the developed models, a study was made of the operation of the proposed climate control system in the time domain for the studied control modes of thermoelectric modules at different values of saturation blocks, according to the results of which it was found that the use of nonlinear control can reduce the time of transients, dynamic control error and oscillation, which unattainable using traditional linear algorithms.

Stationary operation of a thermoelectric system is often not economical due to the impossibility of soft adjustment of the microclimate. The aspect makes relevant the research of the transient modes of Peltier elements and thermoelectric systems built on their basis. The study of the dynamic properties of thermoelectric devices and systems with high accuracy requires the use of complex high-order models, which makes it difficult to obtain analytical solutions. Using the spectral approach and piecewise linear approximation, analytical formulae of the transient modes of Peltier thermoelectric elements for various deviations of control currents are obtained. The calculated relations of piecewise linear approximating functions, spectral densities and time forms of input and output parameters of the model under study are presented. Time diagrams of the temperature response of a particular Peltier element in linear and nonlinear modes are constructed, calculated for the sinusoidal deviation of the control current from the stationary value. [ABSTRACT FROM AUTHOR]

The functioning of a thermoelectric system in a stationary mode is often inefficient because it does not allow flexible control of the temperature regime. The design of thermoelectric devices and systems in transient modes requires identifying their dynamic models, first of all, the control object – the Peltier thermoelectric module. As a rule, well-known identification techniques involve calculating the parameters of a fractional-rational transfer function (or, equivalently, an autoregressive model) of the object of control. At the same time, the increase in the accuracy of identification requirements is associated with significant computational costs. The proposed identification technique requires the determination of the time dependencies of the control current and temperature deviation, the calculation of their spectra based on piecewise linear approximation, and the calculation of the transfer coefficient as the ratio of the spectra of the output and input signals. The calculated relations of piecewise linear approximating functions, spectral densities, and time forms of input and output parameters of the model under study are presented. The amplitude and phase frequency response of the Peltier module are calculated. The low RMS error in the identification of the amplitude-frequency characteristic and phase-frequency characteristic showed the effectiveness of the proposed identification technique. [ABSTRACT FROM AUTHOR]

To ensure the reliability of the physical level of Flying Ad Hoc Networks (FANET), the article substantiates the relevance of the study of stability and dynamic processes of signal formation and processing paths in the terminal and intermediate network equipment. The limitations of the known methods of the theory of automatic control, which make it difficult to perform the analysis of essentially nonlinear high-order signal generators, are shown. To analyze the stability of such formations proposed algorithm based on the use of the Nyquist criterion and approximation of the characteristic polynomial of a device by continuous piecewise functions; to analyze the dynamic characteristics of the algorithm based on spectral method of the input signal approximation and the frequency characteristics of a device by continuous piecewise functions.

The possibility of providing communication in difficult conditions on the basis of Flying Ad Hoc Networks (FANET) requires the use of non-electronic means of communication. It is proposed to use optical communication in the UV-C range in the absence of line-of-sight between the nodes of the FANET network. The general scheme of the optical transmitter and receiver of UV-C range is considered and the review of the components required for its implementation, taking into account the application possibility in highly mobile small-sized UAVs, is carried out. As a result of the analysis of FANET networks with UV-C channel, physical and channel level parameters critical for network performance are revealed. Methods of adaptive change of these parameters in the practical implementation of the UV-C communication system in FANET networks are proposed.